"use strict";
// Encodes |data| into base64url string. There is no '=' padding, and the
// characters '-' and '_' must be used instead of '+' and '/', respectively.
function base64urlEncode(data) {
let result = btoa(data);
return result.replace(/=+$/g, '').replace(/\+/g, "-").replace(/\//g, "_");
}
// Decode |encoded| using base64url decoding.
function base64urlDecode(encoded) {
return atob(encoded.replace(/\-/g, "+").replace(/\_/g, "/"));
}
// Encodes a Uint8Array as a base64url string.
function uint8ArrayToBase64url(array) {
return base64urlEncode(String.fromCharCode.apply(null, array));
}
// Encodes a Uint8Array to lowercase hex.
function uint8ArrayToHex(array) {
const hexTable = '0123456789abcdef';
let s = '';
for (let i = 0; i < array.length; i++) {
s += hexTable.charAt(array[i] >> 4);
s += hexTable.charAt(array[i] & 15);
}
return s;
}
// Convert a EC signature from DER to a concatenation of the r and s parameters,
// as expected by the subtle crypto API.
function convertDERSignatureToSubtle(der) {
let index = -1;
const SEQUENCE = 0x30;
const INTEGER = 0x02;
assert_equals(der[++index], SEQUENCE);
let size = der[++index];
assert_equals(size + 2, der.length);
assert_equals(der[++index], INTEGER);
let rSize = der[++index];
++index;
while (der[index] == 0) {
++index;
--rSize;
}
let r = der.slice(index, index + rSize);
index += rSize;
assert_equals(der[index], INTEGER);
let sSize = der[++index];
++index;
while (der[index] == 0) {
++index;
--sSize;
}
let s = der.slice(index, index + sSize);
assert_equals(index + sSize, der.length);
let result = new Uint8Array(64);
result.set(r, 32 - rSize);
result.set(s, 64 - sSize);
return result;
};
function coseObjectToJWK(cose) {
// Convert an object representing a COSE_Key encoded public key into a JSON
// Web Key object.
// https://tools.ietf.org/html/rfc7517
// The example used on the test is a ES256 key, so we only implement that.
let jwk = {};
if (cose.type != 2)
assert_unreached("Unknown type: " + cose.type);
jwk.kty = "EC";
if (cose.alg != ES256_ID)
assert_unreached("Unknown alg: " + cose.alg);
if (cose.crv != 1)
assert_unreached("Unknown curve: " + jwk.crv);
jwk.crv = "P-256";
jwk.x = uint8ArrayToBase64url(cose.x);
jwk.y = uint8ArrayToBase64url(cose.y);
return jwk;
}
function parseCosePublicKey(coseKey) {
// Parse a CTAP2 canonical CBOR encoding form key.
// https://fidoalliance.org/specs/fido-v2.0-id-20180227/fido-client-to-authenticator-protocol-v2.0-id-20180227.html#ctap2-canonical-cbor-encoding-form
let parsed = new Cbor(coseKey);
let cbor = parsed.getCBOR();
let key = {
type: cbor[1],
alg: cbor[3],
};
if (key.type != 2)
assert_unreached("Unknown key type: " + key.type);
key.crv = cbor[-1];
key.x = new Uint8Array(cbor[-2]);
key.y = new Uint8Array(cbor[-3]);
return key;
}
function parseAttestedCredentialData(attestedCredentialData) {
// Parse the attested credential data according to
// https://w3c.github.io/webauthn/#attested-credential-data
let aaguid = attestedCredentialData.slice(0, 16);
let credentialIdLength = (attestedCredentialData[16] << 8)
+ attestedCredentialData[17];
let credentialId =
attestedCredentialData.slice(18, 18 + credentialIdLength);
let credentialPublicKey = parseCosePublicKey(
attestedCredentialData.slice(18 + credentialIdLength,
attestedCredentialData.length));
return { aaguid, credentialIdLength, credentialId, credentialPublicKey };
}
function parseAuthenticatorData(authenticatorData) {
// Parse the authenticator data according to
// https://w3c.github.io/webauthn/#sctn-authenticator-data
assert_greater_than_equal(authenticatorData.length, 37);
let flags = authenticatorData[32];
let counter = authenticatorData.slice(33, 37);
let attestedCredentialData = authenticatorData.length > 37 ?
parseAttestedCredentialData(authenticatorData.slice(37)) : null;
let extensions = null;
if (attestedCredentialData &&
authenticatorData.length > 37 + attestedCredentialData.length) {
extensions = authenticatorData.slice(37 + attestedCredentialData.length);
}
return {
rpIdHash: authenticatorData.slice(0, 32),
flags: {
up: !!(flags & 0x01),
uv: !!(flags & 0x04),
at: !!(flags & 0x40),
ed: !!(flags & 0x80),
},
counter: (counter[0] << 24)
+ (counter[1] << 16)
+ (counter[2] << 8)
+ counter[3],
attestedCredentialData,
extensions,
};
}
// Taken from
// https://cs.chromium.org/chromium/src/chrome/browser/resources/cryptotoken/cbor.js?rcl=c9b6055cf9c158fb4119afd561a591f8fc95aefe
class Cbor {
constructor(buffer) {
this.slice = new Uint8Array(buffer);
}
get data() {
return this.slice;
}
get length() {
return this.slice.length;
}
get empty() {
return this.slice.length == 0;
}
get hex() {
return uint8ArrayToHex(this.data);
}
compare(other) {
if (this.length < other.length) {
return -1;
} else if (this.length > other.length) {
return 1;
}
for (let i = 0; i < this.length; i++) {
if (this.slice[i] < other.slice[i]) {
return -1;
} else if (this.slice[i] > other.slice[i]) {
return 1;
}
}
return 0;
}
getU8() {
if (this.empty) {
throw('Cbor: empty during getU8');
}
const byte = this.slice[0];
this.slice = this.slice.subarray(1);
return byte;
}
skip(n) {
if (this.length < n) {
throw('Cbor: too few bytes to skip');
}
this.slice = this.slice.subarray(n);
}
getBytes(n) {
if (this.length < n) {
throw('Cbor: insufficient bytes in getBytes');
}
const ret = this.slice.subarray(0, n);
this.slice = this.slice.subarray(n);
return ret;
}
getCBORHeader() {
const copy = new Cbor(this.slice);
const a = this.getU8();
const majorType = a >> 5;
const info = a & 31;
if (info < 24) {
return [majorType, info, new Cbor(copy.getBytes(1))];
} else if (info < 28) {
const lengthLength = 1 << (info - 24);
let data = this.getBytes(lengthLength);
let value = 0;
for (let i = 0; i < lengthLength; i++) {
// Javascript has problems handling uint64s given the limited range of
// a double.
if (value > 35184372088831) {
throw('Cbor: cannot represent CBOR number');
}
// Not using bitwise operations to avoid truncating to 32 bits.
value *= 256;
value += data[i];
}
switch (lengthLength) {
case 1:
if (value < 24) {
throw('Cbor: value should have been encoded in single byte');
}
break;
case 2:
if (value < 256) {
throw('Cbor: non-minimal integer');
}
break;
case 4:
if (value < 65536) {
throw('Cbor: non-minimal integer');
}
break;
case 8:
if (value < 4294967296) {
throw('Cbor: non-minimal integer');
}
break;
}
return [majorType, value, new Cbor(copy.getBytes(1 + lengthLength))];
} else {
throw('Cbor: CBOR contains unhandled info value ' + info);
}
}
getCBOR() {
const [major, value] = this.getCBORHeader();
switch (major) {
case 0:
return value;
case 1:
return 0 - (1 + value);
case 2:
return this.getBytes(value);
case 3:
return this.getBytes(value);
case 4: {
let ret = new Array(value);
for (let i = 0; i < value; i++) {
ret[i] = this.getCBOR();
}
return ret;
}
case 5:
if (value == 0) {
return {};
}
let copy = new Cbor(this.data);
const [firstKeyMajor] = copy.getCBORHeader();
if (firstKeyMajor == 3) {
// String-keyed map.
let lastKeyHeader = new Cbor(new Uint8Array(0));
let lastKeyBytes = new Cbor(new Uint8Array(0));
let ret = {};
for (let i = 0; i < value; i++) {
const [keyMajor, keyLength, keyHeader] = this.getCBORHeader();
if (keyMajor != 3) {
throw('Cbor: non-string in string-valued map');
}
const keyBytes = new Cbor(this.getBytes(keyLength));
if (i > 0) {
const headerCmp = lastKeyHeader.compare(keyHeader);
if (headerCmp > 0 ||
(headerCmp == 0 && lastKeyBytes.compare(keyBytes) >= 0)) {
throw(
'Cbor: map keys in wrong order: ' + lastKeyHeader.hex +
'/' + lastKeyBytes.hex + ' ' + keyHeader.hex + '/' +
keyBytes.hex);
}
}
lastKeyHeader = keyHeader;
lastKeyBytes = keyBytes;
ret[keyBytes.parseUTF8()] = this.getCBOR();
}
return ret;
} else if (firstKeyMajor == 0 || firstKeyMajor == 1) {
// Number-keyed map.
let lastKeyHeader = new Cbor(new Uint8Array(0));
let ret = {};
for (let i = 0; i < value; i++) {
let [keyMajor, keyValue, keyHeader] = this.getCBORHeader();
if (keyMajor != 0 && keyMajor != 1) {
throw('Cbor: non-number in number-valued map');
}
if (i > 0 && lastKeyHeader.compare(keyHeader) >= 0) {
throw(
'Cbor: map keys in wrong order: ' + lastKeyHeader.hex + ' ' +
keyHeader.hex);
}
lastKeyHeader = keyHeader;
if (keyMajor == 1) {
keyValue = 0 - (1 + keyValue);
}
ret[keyValue] = this.getCBOR();
}
return ret;
} else {
throw('Cbor: map keyed by invalid major type ' + firstKeyMajor);
}
default:
throw('Cbor: unhandled major type ' + major);
}
}
parseUTF8() {
return (new TextDecoder('utf-8')).decode(this.slice);
}
}
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